A detailed structural and morphological investigation has been carried out by conventional transmission electron microscopy, high resolution electron microscopy and nanodiffraction methods on vanadium oxide films obtained by reactive rf sputter at a high power discharge (1000 W) and different O2/Ar ratio. Electrical characterization has been also performed in controlled atmosphere in order to investigate the influence of NO2oxidizing gas on the material conductance as a function of deposition parameters. A strict relation between structure, morphology and resistance variation in controlled atmosphere has been observed. ©1997 American Institute of Physics.